A concentration-dependent Butler-Volmer electrode kinetics equation was established by correlating concentration with the overpotential through the Nernst equation.The mass transfer equation and potential distribution equation were optimized based on the supporting electrolyte theory,and the uranium electrorefining model was improved.The cyclic voltammetry curve,constant potential deposition process and constant current deposition process were simulated by using the new model,and the concentration polarization phenomenon and electrode dynamic behavior under different electrolytic conditions were quantitatively analyzed.The simulated cyclic voltammetry curve is in good agreement with the experimental results,verifying the accuracy of the model.Through modeling,the distributions of U(III)concentration,potential,and current density in the molten salt and on the surface of electrode were obtained.The key parameters such as diffusion layer thickness,limiting diffusion current and deposition layer thickness were predicted,and the driving force changes caused by concentration polarization during constant current deposition and constant potential deposition were compared.The numerical model established in this study can be used as a powerful tool to optimize process parameters and design process equipment,and has important physical significance for deepening understanding of uranium electrorefining mechanism.
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